Modbus protocol
Modbus integration: the registers of your inverter and meter on one screen
We have the data model. We are looking for the register map.
For inverters, meters, boilers and industrial devices: what is already inside the system and what depends on the device documentation.
In short
Modbus is a protocol for reading and writing registers: the device keeps them, the client asks for them. HoumeOS describes Modbus TCP and RTU/RS485 in the integration catalog and provides guides with a real TCP check of the address. The contract and the panel are ready; the driver that reads the registers themselves is still to come — and we say it openly.
What Modbus is and why we want it
Modbus is old, clear and very spread out: a device has numbered registers, and a client reads and writes them over a serial line (RTU/RS485) or through a TCP port. That is exactly why solar inverters, energy meters, some heat pumps and nearly every industrial device have it. For HoumeOS Modbus is not the goal but a path: the data enters home/v1 and takes part in the same rules as everything else.
- The registers carry the numbers: power, voltage, state of charge, energy for the day
- Units and scales come from the device documentation, not from us
- The read period is chosen so the history does not drown in noise
What is ready today
The catalog describes Modbus TCP and RS485 as transports with direction, medium and whether the required dependency is present. The panel provides guides for address and port and makes a real TCP test request, so you can see whether anything is behind the address at all. The editor keeps the settings on the server, and the device registry separates a common confusion: "the devices work" and "the transport is alive" are two different truths.
What is still to come: the driver that reads the registers
Reading the registers themselves is the job of the Modbus driver, and it is not ready. What is needed is a register map from the device documentation, scales and units, and the behaviour when a reply is missed. This is work per site and per documentation — which is exactly why we do not claim to read your inverter today.
What we need from you
The register map from the manufacturer documentation: which addresses carry which quantities, what the scale is, where the signs are, which port and which line are used. If you already have Modbus TCP access, checking the address takes minutes through the guides in the panel. If you only have RS485, you also need a converter into the LAN — and that is chosen together with a survey of the site.
Where the numbers go
Once translated, they are like any other state: the Energy screen with the flow production → battery → grid → consumption, curves by hours and days, rules with conditions and bans, costs by tariffs, history for 7/31/13 months. The rules run on the server, so they work without the internet — and without the cloud account of the inverter manufacturer.
What works today and what is coming
We do not present upcoming work as available. This list matches the roadmap.
Works today
- Modbus TCP and RTU/RS485 are described in the integration catalog as transports
- Guides with address and port and a real TCP test request to the device
- The integration editor with settings kept on the server, not on the tablet
- The Energy screen: flow, curves by hours and days, tariffs and costs, history
Coming soon
- A driver that reads the registers by the map of the device and writes them into home/v1
- A clear state when a reply is missed, instead of silent zeros
Later
- Ready drivers for specific inverter and meter brands — written for a site on request
- OCPP for external chargers and HTTPS remote access
Frequently asked questions
How is a Modbus device integrated?
We expect a register map: address, port, units, read period. The panel describes the transport and checks whether the address answers; reading the registers themselves is the driver's job and it is still to come. For solar inverters and energy meters we are ready to write the driver together with your installer if the documentation exists.
Modbus TCP or RTU?
TCP is easier: the device or the converter is reachable at an IP address and a port, and the address check happens from the panel. RTU/RS485 needs a line and a converter into the LAN. Both variants are described in the catalog as transports; for both, the missing link is the same one — the driver that reads the registers.
Will HoumeOS read my energy meter today?
Not today. The model is ready — power, energy for the day, import and export, tariffs and costs, curves by hours, days and months. What is missing is the connection to the real device, that is the Modbus driver. Which is also why we present it as the next roadmap step rather than an available integration.
What happens when a device goes silent?
We separate two things: the state of the device and the state of the transport. The device registry shows "offline", "online" or "unknown", and the card shows how long a dropped device has been silent. A stopped transport raises a warning through the alert engine, instead of quiet zeros in the charts.
We show the system on a live screen
The demo starts from your question: which devices, which protocols, which scenarios.